Welch Run is a long 1st order tributary to Buffalo Creek in Washington County, Pennsylvania.
Welch Run rises in a pond about 1.5 miles northeast of Dunsfort, Pennsylvania, in Washington County and then flows southwest to join Buffalo Creek at Dunsfort.
Welch Run drains of area, receives about 40.1 in/year of precipitation, has a wetness index of 288.69, and is about 88% forested.